code: def test_extension_in_blacklist(app, status, warning):
      app.setup_extension("sphinxjp.themecore")
      msg = strip_escseq(warning.getvalue())
      assert msg.startswith(
          "WARNING: the extension 'sphinxjp.themecore' was"
      )
  
file_path: sphinx/tests/test_application.py
imports: import shutil
  import sys
  from io import StringIO
  from pathlib import Path
  from unittest.mock import Mock
  import pytest
  from docutils import nodes
  import sphinx.application
  from sphinx.errors import ExtensionError
  from sphinx.testing.util import SphinxTestApp, strip_escseq
  from sphinx.util import logging
label_desc: Use image node_id 5 for calling a global function with example usage: test_extension_in_blacklist(app, status, warning) without return types